Furnace-roof.



P. J. GRIFFIN. .FURNACE ROOF.

APPLICATION FILED 5.724. 1911.

1,274,034. Patented. July 30, 1918-.

UNITED STATES PATENT OFFICE.

PATRICK JOSEPH GRIFFIN, 0F ANNISTON, ALABAMA.

FURNACE-ROOF.

Specification of Letters Patent. Patented July 30, 1918.

Application filed February 24, 1917 Serial No. 150,695.

To all whom it may concern:

Be it known that I, PATRICK JOSEPH GRIFFIN, a citizen of the United States, and resident of Anniston, in the county of Calhoun and State of Alabama, have invented certain new and useful Improvements in Furnace-Roofs, of which the following is a specification. I

My invention relates to metallurgical furnaces and has particular reference to a novel A roof adapted for use in connection therewith. v

It is well known that owing to the in.- tense heat, particularly in electric furnaces,

the roof structure is likely to cause considerable trouble and consequently to delay the operations and reduce the efficiency of the plant. An object of the present invention is to so construct and arrange the elements going to make up the roof structure that a roof may be built apart from the furnace and, when occasion requires, be removed bodily and placed in position over the furnace following the removal of the defective roof. The desired result is accomplished by constructing the roof in the form of a stable dome, in the case of a round furnace, or in the form ofan arch in the case of-a square or otherwise shapedi'urnace. I secure the desired results by providing a metallic ring in the case of the circular roof, the ring acting as a support for skew bricks. Concentric rows of tapered bricks are associated with the skew bricks, a keystone brick event of the failureof the roof on the furnace it may be removed and the new roof replaced thereon without waiting for the furnace to cool down, as Would be necessary in event extensive repairs were-to made.

Roofs for use in connection with electric furnaces are commonly composed of silica brick, and as this material has a relatively high coefficient of expansion provision must be made therefor. To this end it is common to insert thin strips of wood or similar non-refractory material. When the roof becomes highly heated this material is detain of the expansion strips burn out before others thereof, in which case the adjacent bricks are likely to drop down a certain distance and in some cases to drop into the furnace. In event they project downwardly beyond the adjacent bricks, the projecting portion will flake andspall off. In event of the unequal location orpositioning of the bricks, the arch is deprived of the capacity for equal expansion and adjacent bricks are likely to be bursted. Provision is made in my design for permitting equal expansion and contraction and preventin the loosening and dropping of any bricis following the destruction of the expansion strips. The result is secured'by providing lateral ribs or projections in certain of the key bricks, which projections overlie portions of adjacent bricks thereby preventing relative vertical movement therebetween. At the same time the bricks are permitted. to expand as necessary.

yimprovement is important also from a safety standpoint, as itis possible by the use 'of my construction for operatorsto walk upon the roof with safety while makin repairs around the electrodes.

other objects and advantages will appear hereinafter.

The invention will be more readily understood by reference to the accompanying drawings in which:

Figure 1 is a plan view of the roof for .an electric furnace constructed in accordof spacedeyes 11, are riveted thereby providing means adapted to be engaged by a crane for lifting the roof as required. It will be understood that the roof is domeshaped and is'intended to be built overa suitably shaped form. In the present instance the roof is shown-as comprising six concentric rows of bricks, 12, 13, 14, 15, 16, 17, and a keystone brick 18. Suitable electrode openings 19, are shown in the roof. The bricks in the row'12, are termed skew bricks andare confined between lower and upper angles 20, 21, riveted to the rings 10. The inner face of the skew bricks is inclined and stepped, the recess 22, near the upper edge thereof, accommodating a laterally projecting rib 23, on the upper edge 'of the key bricks 13. The inner surface of the bricks 13, are likewise inclined and recessed to accommodate the lateral rib 24, on the key bricks 14. The row of bricks 15, differ somewhat in that their upper edges are above the contour line defined by the key bricks 13, 14, and the outer incline of the bricks is continued upwardly thereby providing an ovehanging or projecting portion 25', which overlies the key bricks 14. The upper surface of the rows, 15, 16, 17 of the bricks is preferably in a horizontal plane. All the bricks are tapered and are maintained in proper relation by the action of the key bricks 13, 14.

In order to provide for expansion following the heating of the roof, I locate wood strips 26, 27, 28, between the rows 12, 13, 14, 15 of bricks, these being applied when the roof is built. The intense heat of the furnace will, however, cause these strips to be destroyed and, therefore, permit the necessary expansion. Should any of the strips burn out before others thereof, the key bricks .cannot be displaced vertically as they will be retained by the interengaging ribs and recesses.

A furnace roof constructed in accordance with my invention will be found to retain its shape and efliciency .for long periods of time. When, however, extensive repairs become necessary it may be very quickly removed and replaced with another roof.

While I have shown the invention in as sociation with a roof for a circular furnace, many of the advantages thereof will accrue in roofs having different shapes, and I do not wish to be limited to the exact form shown herein.

I claim: 1. A furnace roof comprising abutments, a centralroof portion, and expansion joint roof portions including destructible spacing members between .the central roof port-ion and the abutments.

2. A furnace roof comprising a central roof portion, an abutment surrounding said central roof portion, and an expansion joint portion including destructible spacing maexpansion joint roof portion including two rows of bricks, adjacent bricks of the rows having a socket and projection supporting interengagement, and a compressible'filler between said bricks.

4. A furnace roof comprising a ring, a skewback within and supported by the ring, an internal flange carried by the ring and disposed on top of the skewback, a central roof portion, and an expansion joint'roof portion between the skewback and the central roof portion, said expansion roof portion including two rows of bricks, there being a socket and projection inter-fitting support between the rows of bricks and also between the outer row of bricks and the skewback, and a compressible filler between the rows of bricks and also between the outer row of bricks and the skewback.

5. A furnace roof comprising abutments,

a central roof portion between the abutments, and an expansion joint roof portion between the central roof port1on and each abutment, the expansion oint roof port1on including rows of bricks, one row of bricks having a groove at the top thereof, an adjacent row of bricks having a tongue fitting in the groove and suppoiting said adjacent row on said one row, anda compressible filler between said rows of bricks.

6. A furnace roof comprising a ring, a skewback within and supported by the ring, a central roof portion, and an expansion joint roof portion including destructible spacers between the skewback and the central roof portion.

7. A furnace roof comprising a ring, a skewback within and supported by the ring, an internal flange carried by the ring and disposed on top of the skewback, a central roof portion, and an expansion joint roof portion between the skewback and the central roof portion.

Signed at Anniston', Alabama, this 19th day of February, A. D. 1917.

PATRICK JOSEPH GRIFFIN.

Witnesses:

J. L. GREEN, M. C. LISER. 

